摘要
煤岩孔隙结构对煤层气储集与渗流具有重要控制作用.基于恒速压汞、低温液氮吸附及低场核磁共振等测试,对比分析了新疆山前冲断带浅部与深部高挥发分烟煤(HVBC)样品孔隙-喉道结构差异及其对不同深度煤层气勘探开发的影响.结果如下:(1)恒速压汞实验表明,相对浅部HVBC样品,深部HVBC样品大孔半径峰值大于浅部,且喉道尺寸分布非均质性更强,孔喉半径比更大.(2)低温液氮实验表明,相对浅部HVBC样品,深部HVBC样品微孔和过渡孔弱于浅部,且主要发育贯通型圆柱孔和开放型层状孔.(3)低场核磁共振实验表明,相对浅部HVBC样品,深部HVBC样品中孔更为发育,大孔及裂隙发育较差.(4)浅部HVBC煤岩受成煤作用后煤层深埋作用与折返抬升作用影响,呈现微孔、过渡孔及大孔和裂隙发育程度更好且低孔喉半径比特征;相比之下,深部HVBC煤岩受深埋压实作用影响,呈现弱改造效应下的高孔喉半径比特征.
The pore structure of coal plays a critical controlling role in coalbed methane storage and seepage.Based on constant-rate mercury intrusion porosimetry,low-temperature nitrogen adsorption,and low-field nuclear magnetic resonance tests,this study comparatively analyzes the differences in pore-throat structures between shallow and deep high-volatile bituminous coal(HVBC)samples from the foreland thrust belt of Xinjiang and their implications for coalbed methane exploration and development at varying depths.The key findings are as follows:(1)Constant-rate mercury intrusion porosimetry results indicate that,compared to shallow HVBC samples,deep HVBC samples exhibit a larger peak macropore radius,stronger heterogeneity in throat size distribution,and a higher pore-throat radius ratio.(2)Low-temperature nitrogen adsorption results reveal that deep HVBC samples have less developed micropores and mesopores than shallow’s,with predominantly interconnected cylindrical pores and open slit-shaped pores.(3)Low-field nuclear magnetic resonance results demonstrate that deep HVBC samples contain more mesopores but fewer macropores and fractures compared to shallow’s.(4)Shallow HVBC has betterdeveloped micropores,mesopores,macropores,and fractures,along with a lower pore-throat radius ratio,influenced by post-coalification deep burial followed by uplift and exhumation.In contrast,deep HVBC exhibits a high porethroat ratio under weak modification effects due to deep burial and compaction.
作者
任艳泽
李鑫
谢安
王子强
王兴刚
焦立新
曹志雄
李斌
REN Yanze;LI Xin;XIE An;WANG Ziqiang;WANG Xinggang;JIAO Lixin;CAO Zhixiong;LI Bin(Xinjiang Key Laboratory of Continental Dynamics and Mineralization Prediction in the Central Asian Orogenic Belt,Xinjiang University,Urumqi Xinjiang 830017,China;Huairou Laboratory Xinjiang Research Institute,Urumqi Xinjiang 830000,China;Research Institute of Exploration and Development,PetroChina Tuha Oilfield Company,Hami Xinjiang 839000,China)
出处
《新疆大学学报(自然科学版中英文)》
2025年第6期654-664,共11页
Journal of Xinjiang University(Natural Science Edition in Chinese and English)
基金
新疆维吾尔自治区天山英才计划“新疆前陆冲断带深部煤系天然气形成机制与富集机理”(2022TSYCCX0043)
新疆维吾尔自治区科技重大专项“利用二氧化碳提高新疆难开采煤层气采收率技术体系研发”(2022A03015-3).
关键词
煤层气
孔隙结构
恒速压汞
低温液氮吸附
低场核磁共振
coalbed methane
pore structure
constant-rate mercury intrusion porosimetry
low-temperature nitrogen adsorption
low-field nuclear magnetic resonance
